libc/src/sys/mman/linux/madvise.cpp

   1 //===---------- Linux implementation of the POSIX madvise function --------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "src/sys/mman/madvise.h"
  10
  11 #include "src/__support/OSUtil/syscall.h" // For internal syscall function.
  12 #include "src/__support/common.h"
  13
  14 #include "src/errno/libc_errno.h"
  15 #include <sys/syscall.h> // For syscall numbers.
  16
  17 namespace LIBC_NAMESPACE {
  18
  19 // This function is currently linux only. It has to be refactored suitably if
  20 // madvise is to be supported on non-linux operating systems also.
  21 LLVM_LIBC_FUNCTION(int, madvise, (void *addr, size_t size, int advice)) {
  22   int ret = LIBC_NAMESPACE::syscall_impl<int>(
  23       SYS_madvise, reinterpret_cast<long>(addr), size, advice);
  24
  25   // A negative return value indicates an error with the magnitude of the
  26   // value being the error code.
  27   if (ret < 0) {
  28     libc_errno = -ret;
  29     return -1;
  30   }
  31
  32   return 0;
  33 }
  34
  35 } // namespace LIBC_NAMESPACE